Cellulosic spinning solution



mama M. 2, 19 1 UNITED STATES PATENT OFFICE North American RayonCorporation, New York, N. Y., a corporation of Delaware No Drawing.

8 Claims.

The present invention relates to a process of producing artificial silkof cellulosic origin having bactericidal properties, especially whenbeing contacted by vapors or liquid substances.

The primary obiect of this invention relates to the production ofantiseptic, cellulosic filaments and yarns containing one or morecolloidal metals in combination with one or more dissimilar, colloidalmetal salts.

10 Another object of my invention has to do with a process of increasingthe bactericidal powers of colloidal metals and colloid metal compoundsby irradiating them with ultra-violet rays prior to their incorporationinto cellulosic spinning sou lutions.

Other objects of my invention will become apparent to those skilled inthe art after a study of the following specification.

I am well aware that it has, heretofore, been proposed to use colloidalmetals as disinfectants (vide Rideal, "Disinfection and Sterilization,1921, pages 206-9), and to impregnate textile fibers with metallic saltsand colloidal hydroxides (vide U. 8. Patents Nos. 22,362, 1,482,416,

25 1,536,254, and 71,717,483) to prevent fungous growth thereon.

However, I have found by experimentation that a colloidal metal or acolloidal metal compound does not have a sumcient sterilizing powerafter so being imbedded into cellulosic flbers. After a thoroughinvestigation of the effect of colloidal metals as well as colloidalmetal compounds upon non-pathogenic and pathogenic microorganisms, suchas bacteria and molds, I have found that the 35 bactericidal effect ofthe aforementioned substances can be substantially increased andaccelerated by distributing a combination of colloidal metals andcolloidal metal compounds in a spinning solution or illament ofcellulosic origin.

In order to increase and/or accelerate the bactericidal properties ofcolloidal metals and metal compounds, it is necessary to-select at leastone metal in combination with a metal compound to 45 form a bactericidalagent, i. e., disinfectant. Thus, I may combine, for example, copperwith euprous oxide or sulfide, cupric selenide with cuprous oxide, etc.I may also combine an electro-positive element chosen from the lightermetsis of the second and third periodic groups and Application October20, 1934 Serial No. 749,271

an electro-negative electrode element chosen from the oxygen family inthe sixth periodic group, for example, magnesium as the electropositiveelectrode element and a selenide of a. copper alloy as theelectro-negative electrode element all of these elements beingcolloidally dispersed.

When microorganisms, such as bacteria, molds. etc., are distributed in aliquid phase and subsequently a solid phase, such as acolloidal metal 10added thereto, they are killed after a while and the liquid phasebecomes sterile. The time consumed to paralyze the protoplasma ofmicroorganisms depends naturally upon the species of microorganismstreated, the chemical composition and temperature of the nutritivesolution and the amounts and chemical properties of the colloidal metalsand metal compounds used as disinfectants. The physico-chemicalprinciples underlying this sterilization are unknown. although thetheory has been advanced that the colloidal metal particles becomeadsorbed to the membranes of the microorganisms and in turn preventproper assimilation of nutritive substances. Other investigators haveclaimed that invisible rays are emitted by the colloidal particles whichparalyze protoplasma. I have been unable to definitely find the causewhy cells of microorganisms are much more rapidly killed in the presenceof a colloidal metal and a dissimilar colloidal metal compound. Whetheror not this theory is correct, I have definitely found thatmicroorganisms are much more rapidly killed by disinfectants comprisingone or more disslmilar metals in combination with one or a pinrality ofcolloidal metal compounds, than by a single colloidal metal, two or morecolloidal metals unable to set up a potential diflerence, a singlecolloidal metal salt or a plurality of colloidal 40 metal salts unableto set up a potential difference. Table I depicts the results obtainedby using various colloidal substances, in accordance with the presentinvention, to sterilize aqueous stupensions of Bacillus coli. Toobtain'comparable resuits, aqueous suspensions of Bacillus coli wereprepared by inoculating it into sterile water. Subsequently equalamounts of this bacterial suspension were transferred by means of aplatimnn loup into test tubes containing identical quantities so Table!Beau colt M I loci broth-gelatin at 37.5 C.

One loop of bacterial suspension inoculated into every test tubecontaining 10 cc. of gelatine. 0.1 g. of disinfectant in 1 cc. ofdistilled water and 0.01 g. gelatine as protective colloid.

Tim. of treatment in minutes xxx xxx

xxx

com dkinloctants equal amounts of each ingredbnt were used to make up0.1 g. of disinfectant, for example 0.05 g. copper plus 0.15 g. wprousoxide, etc.

I have, furthermore, found that colloidal metals and metal salts,irradiated with ultra-violet rays, prior to being used as disinfectants,have a greater bactericidal power than non-irradiated ones. Althoughultra-violet rays stimulate the aforementioned colloidal disinfectantsto a higher degree than day light, it is to be noted that a prolongedirradiation fails to increase the bactericidal eil'ect of a disinfectantbeyond a fixed limit. This limit varies for each metal, metal salt andcompositions thereof and must be determined by experiment, in otherwords, each colloidal agent has a definite optimum time of irradiation.Over-exposure to ultra-violet rays does not deleteriously efiect thecolloidal disinfectants, but it should be avoided for reasons ofeconomy. I am unable to define the complex reactions which evidentlytake place in such irradiated dispersions, but I have definitely foundthat the agents, cited above, substantially increase their bactericidalpower after being irradiated. This stimulation by means of irradiationis so pronounced that even the walls of glass flasks in which they arekept acquire bactericidal properties. When, for example, all colloidalmetals and/or colloidal metal salts are removed from such a flask byrinsing and the same fllled with a suspension of virulent bacteria, theywill be killed after standing for some time. This experiment can berepeated several times, the glass walls acting as disinfectants in theabsence of colloidal particles, at least I have been unable to detectwith the microscope any particle adsorbed to the glass walls of suchflasks. Although I am unable to explain this phenomena, a markedincrease of the bactericidal power of my agents is obtained bypro-irradiation. Table II depicts some results obtained by this method.

Table II Eflcct of irradiation All dispersions were irradiated withultra-violet rays in open glass dishes rior to being used asdisinfectants. After inoculation he tubes were kept in a dark incubator(see Table 1).

Similar results were obtained with spores of mucor and oidium species,although they are more resistant to destruction. After standing in thedark for 14 days the irradiated colloidal disinfectants were againcompared with the nonirradiated ones. The pre-irradiated disinfectantshad retained a higher sterilizing power than the non-irradiated ones. Itis to be noted, however, that the stimulation, obtained bypro-irradiation, slowly abates on standing, and that it may be revivedby a second irradiation, etc. I

The colloidal dispersions may be prepared by well known processes toform suitable disinfectants. The metals may be dispersed by electricalmeans and. held in aqueous suspension by adding thereto suitableprotective colloids, such asgelatine, agar, gums, alginates, casein,soluble silicates, protalbic acid, etc, Colloidal metals may also beformed by chemical precipitation in aqueous solutions. Subsequently thebyproducts may be removed by dialysis, the colloidal particles suspendedin water and protective colloids added thereto as stabilising agents.Colloidal salts may be prepared by grinding, for example, oxides,hydroxides, sulfides, etc., in pebble or colloid mills to microscopicfineness. They may also be formed by chemical reaction and purified bydialysis.

Colloidal copper, for example, may be prepared in the following manner.A 20% aqueous solution of copper sulphate, containing about 10 to 20%saccharose is boiled for a few minutes and subsequently diluted with anequal amount of dis tilled water, this comprising solution No. 1.Solution No. 2 consists of a 14% aqueous solution of sodium or potassiumhydroxide. Solution No. 3 is prepared by adjusting sulphuric acid that 1solution. Solution No. 4 is obtained by dissolving approximately 5 g. ofgelatlne in ccs. of distilled water. After having prepared solutionsl to4, 10 cos. of solution No. 1 are mixed with 40 cos. of solution No. 4and the mixture boiled on a water bath for a. few minutes. About 5 to 6cos. of solution No. 2 are added to the hot mixture to precipitatecolloidal cuprous hydroxide. This cuprous oxide may be purified bydialysis'and used in combination with colloidal metals according to myinvention. To form colloidal copper from cuprous hydroxide, the solutionis again boiled and subsequently about 3 cos. of solution No. 3 added.Red colloidal copper is spontane cc. thereof corresponds to 2 cos. ofthe hydroxide 60 vinyl alcohol.

ously precipitated'which is purified by dialysis. The colloidal copperdispersion tends to coagulate on prolonged standing, but it may bestabilized by a small addition of alcoholic potassium citrate solution,etc. Instead of using sulphuric acid to form colloidal copper, any acidmay be employed in which colloidal copper is insoluble. Such colloidalmetals may be also prepared by reducing water-soluble metal salts withaldehydes, p-aminophenol, etc., 1 g. of gold chloride, for example, isdissolved in a few cos. of distilled water and added to 500 cos. of a10% aqueous solution of After addition of a mixture of 40 cos. offormaldehyde and 40 cos. of n-sodium carbonate solution, colloidal goldis precipitated which may be purified by dialysis. Instead of vinylalcohol, other protective colloids may be used. Ammonia added towater-soluble chromium chloride, for example, in the presence of vinylalcohol results in the formation of colloidal chromium hydroxide. In a.similar manner other colloidal metal hydroxides may be formed. Colloidalmetals and metal compounds may be also prepared in the following manner.10 g. of silver nitrate is mixed with 100 g. of cholesterine orphytosterine and the mixture heated to about 250 C. until a silvermirror appears on the surface of the composition. The compositioncontaining colloidal silver may be dissolved in oils, such as olive oil,Turkey red oil, etc. When lead peroxide is treated in this manner in thepresence of silver nitrate, a mixture of colloidal lead and silver isobtained which. may be dissolved in oils. By melting, for example,cobalt nitrate with uranyl nitrate in cholesterine, colloidal cobaltoxide and uranyl oxide is obtained, which may be taken up in chloroformor oils. When such metal organosols are incorporated into cellulosicspinning solutions, bactericidal filaments are obtained which aresimultaneously delustered.

Example This invention is naturally not limited to the production offilaments or yarns, but also antiseptic ribbons, sheets and the like maybe formed from the spinning solutions. In this manner it is possible toproduce sterile sausage casings, wrapping materials, filter cloths, etc.

I wish to point out that the above example is merely illustrative, and Ido not wish to be limto the use of all of these substances and noothers,nor the exact proportions and concentrations, set forth above, as theomission of some ingredients or a slight variation of proportions willnot adversely aflect the final products, although it may somewhat varythe relative characteristics of such products, resulting from suchvariations. The expression colloidal metal salts in the specification aswell as in the claims means: metal salts which are substantiallyinsoluble in cellulosic spinning solutions, which are, thus, dispersabletherein and which are able to set up a more or less large potentialdifierence with a dissimilar, colloidal metal in the presence of minutequantities of electrolytes. Modifications may be made in details of themeth'od and the product without departing from the spirit and scope ofmy invention, as defined by the appended claims.

I claim:

l. A spinning solution for the manufacture of products havingbactericidal properties comprising a cellulosic spinning solution of thegroup consisting of viscose, cuprammonium cellulose, cellulose estersand cellulose ethers, a colloidal metal and a dissimilar colloidal metalsalt dispersed therein, said metal salt being able to set up a potentialdifference in the presence of a colloidal metal and an electrolyte, andsaid metal and metal salt being chemically inert to said spinningsolution.

2. A spinning solution for the manufacture of products havingbactericidal properties comprising a cellulosic spinning solution of thegroup consisting of viscose, cuprammonium cellulose, cellulose estersand cellulose ethers, a colloidal metal and a dissimilar metal salt,said metal and metal salt being pre-irradiated with ultra-violet raysand able to set up a potential difference in the presence of anelectrolyte, and said metal and metal salt being chemically inert tosaid spinning solution.

3. Aspinning solution for the manufacture of products havingbactericidal properties comprising a viscose spinning solution, acolloidal metal and a dissimilar colloidal metal salt, said metal saltbeing able to set up a potential difierence in the presence of acolloidal metal and an electrolyte, and said metal and metal salt beingchemically inert to said spinning solution.

' 4. A spinning solution for the manufacture of products havingbactericidal properties comprising a viscose spinning solution, acolloidal metal and a dissimilar colloidal metal salt, said metal saltbeing pro-irradiated with ultra-violet rays and able to set upapotential-difference in the presence of a colloidal metal and anelectrolyte, and said metal and metal salt being chemically inert tosaid spinning solution.

5. A bactericidal cellulosic product of the group consisting of viscose,cuprammonium cellulose, cellulose esters and cellulose ethers containinga colloidal metal and a dissimilar colloidal metal salt uniformlydispersed therein.

6. A bactericidal cellulosic product of the group consisting of viscose,cuprammonium cellulose, cellulose esters and cellulose ethers containinga colloidal metal and a dissimilar colloidal metal salt uniformlydispersed therein, said metal and metal salt being pr-irradiated withultra-violet rays.

7. A bactericidal viscose product containing a colloidal metal and adissimilar colloidal metal salt uniformly dispersed therein.

8. A bactericidal viscose product containing a colloidal metal and adissimilar colloidal metal salt uniformly dispersed therein, said metaland metal salt being pre-irradiated with ultra-violet rays.

RUDOLPH S. BLEY.

